An alternative propellant is being tested for safety in the new ipratropium bromide aerosol. The multi-center study involves 400 subjects, 3 proposed for IUSM GCRC, with chronic obstructive pulmonary disease (COPD) Participants will receive aerosol inhalations of either ATROVENT, or placebo (inhalers containing all ingredients except iprotropium bromide). Participants will then be monitored for 14 weeks, and tested for the safety of the aerosol.